1. Research Assistant, Urban Informatics Laboratory, Dept. of Civil and Environmental Engineering, Stanford Univ., 473 Via Ortega, Room 269B, Stanford, CA 94305.
2. Staff Researcher, Urban Informatics Laboratory, Dept. of Civil and Environmental Engineering, Stanford Univ., 473 Via Ortega, Room 269B, Stanford, CA 94305.
3. Assistant Professor, Urban Informatics Laboratory, Dept. of Civil and Environmental Engineering, Stanford Univ., 473 Via Ortega, Room 269A, Stanford, CA 94305 (corresponding author).